Inhalation device

The present invention relates to an inhalation device, in particular, an inhalation device for administering a powdered medicament by inhalation from a blister pack.

It is known in the treatment of respiratory conditions to make use of dry powder inhalers comprising a suction tube arranged so that it is able to cooperate with a blister pack containing a plurality of individual blisters each holding a dose of powdered medicament.

Reference should now be made to WO 97/40876 which discloses an inhalation device comprising a suction tube and a blister pack assembly. The blister pack assembly is in the form of a carrier which holds the blister pack. The carrier is configured such that the upper surface has a plurality of holes which sit above the blisters in the blister pack thereby enabling the distal end of the suction tube to penetrate the blisters as and when required.

The object of the present invention is to provide an improved inhalation device of this kind which has a superior construction and is more user-friendly. In particular, the construction should be light and compact whilst retaining sufficient rigidity and strength bearing in mind that the user may have to administer the powdered medicament at frequent intervals. Moreover, the construction should be such that the user cannot misuse the inhalation device since incorrect delivery of the powdered medicament could be potentially harmful to the user.

According to the present invention, there is provided an inhalation device for administering a powdered medicament by inhalation comprising a suction tube through which the medicament is drawn on inhalation by a user, a blister pack and a housing which carries the blister pack, the suction tube being removably connected to the housing and having a distal end which can interact with the blister pack and a proximal end through which the user inhales, characterised in that the inhalation device further comprises biasing means which move the suction tube into a position where it is biased away from the housing surfaces to facilitate grasping by the user when the inhalation device is ready for use.

Preferably, the biasing means form a connection for the suction tube to the housing.

Preferably, the biasing means raise the suction tube away from the housing surfaces.

Preferably, the housing is a carrier for the blister pack.

Preferably, the distal end of the suction tube is removably hinged on the carrier.

Preferably, the biasing means is an elongate resilient member, one end of which is connected to the suction tube and the other end of which is connected to the carrier.

Preferably, the resilient member biases the suction tube on the hinge from a first position where the suction tube is able to lie adjacent to the carrier to a second position where the suction tube is raised away from the carrier.

Preferably, the resilient member is in the form of a strip constructed with a protruding spine running centrally along the length of the strip.

Preferably, the end of the resilient strip which is connected to the suction tube has a thickened portion.

Preferably, the resilient member is connected to the carrier by a hooked formation.

Preferably, the hooked formation connects the resilient member to the carrier in such a way as to allow a sideways and/or twisting movement during transfer of the suction tube between blisters.

Preferably, the biasing means is a sprung element which forms part of the hinge on the carrier.

Preferably, the sprung element biases the suction tube on the hinge from a first position where the suction tube is able to lie adjacent to the carrier to a second position where the suction tube is raised away from the carrier.

Preferably, the hinge comprises a holding element for cooperation with the distal end of the suction tube.

Preferably, the suction tube is connected to the holding element by a flexible elongate member.

Preferably, the inhalation device further comprises an outer case for holding the suction tube and carrier, wherein the outer case is hinged such that the user is able to close the outer case against the biasing action of the biasing means thereby making the suction tube lie adjacent to the carrier when not in use and the outer case is closed.

Preferably, the housing comprises an outer case and a carrier which carries the blister pack.

Preferably, the distal end of the suction tube is removably hinged on the outer case.

Preferably, the biasing means is an elongate resilient member, one end of which is connected to the suction tube and the other end of which is connected to the carrier.

Preferably, the resilient member moves the suction tube on the hinge from a first position where the suction tube is able to lie adjacent to the outer case to a second position where the suction tube projects away from the outer case.

Preferably, the resilient member is in the form of a strip with the resilient member is in the form of a strip with one or more preformed waves which can unfold under tension.

Preferably, the end of the resilient strip which is connected to the suction tube has a thickened portion.

Preferably, the resilient strip is connected to the carrier by a hooked formation.

Preferably, the hooked formation connects the resilient member to the carrier in such a way as to allow a sideways and/or twisting movement during transfer of the suction tube between blisters.

Preferably, the biasing means is a sprung element acting on the suction tube.

Preferred embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings, of which:

FIG. 1 is a perspective view of the first embodiment of the inhalation device when enclosed in an outer case;

FIG. 2 is a perspective view of the inhalation device in FIG. 1 when the outer case has been opened;

FIG. 3 is a perspective view of the inhalation device in FIG. 2 showing how the suction tube and blister pack assembly are inserted into the outer case;

FIG. 4 is a perspective view of the inhalation device when removed from the outer case;

FIG. 5 is an exploded view of the elements of the inhalation device in FIG. 4;

FIG. 6 is an exploded view of the elements attached to the upper tray of the blister pack assembly;

FIG. 7 is a plan view of the blister pack in FIG. 5;

FIG. 8 is a sectional view in direction X—X of the blister pack in FIG. 7;

FIG. 9 shows the detail of a single blister and slit in plan view;

FIG. 10 is a sectional view through the blister and slit in FIG. 9 (with a modified slit);

FIG. 11 is a view of one side of the body of the suction tube;

FIG. 12 is a sectional view in direction X—X in FIG. 11;

FIG. 13 is a view of the body of the suction tube in direction A in FIG. 11;

FIG. 14 is a sectional view in direction X—X in FIG. 13;

FIG. 15 is a view from above of the proximal end of the body of the suction tube in FIG. 11;

FIG. 16 is a view from below of the distal end of the body of the suction tube in FIG. 11;

FIG. 17 is a perspective view of the external sleeve of the suction tube and resilient strip;

FIG. 18 is a view from one side of the external sleeve and resilient strip in FIG. 17;

FIG. 19 is a view in direction A in FIG. 18;

FIG. 20 shows detail of the guide arm of the suction tube in FIG. 18;

FIG. 21 is a sectional view in direction X—X in FIG. 18;

FIG. 22 shows detail of the connection of the resilient strip to the external sleeve of the suction tube;

FIG. 23 is a sectional view in direction X—X in FIG. 21;

FIG. 24 is a plan view of the upper tray of the carrier;

FIG. 25 is a sectional view in direction X—X in FIG. 24;

FIG. 26 is a view in direction A in FIG. 24;

FIG. 27 is a plan view of the lower tray of the carrier;

FIG. 28 is a sectional view in direction X—X in FIG. 27;

FIG. 29 is a sectional view in direction Y—Y in FIG. 27;

FIG. 30 is a sectional view in direction Z—Z in FIG. 27;

FIGS. 31 to <b>37</b> are various views of the inhalation device when the suction tube has been inserted into a blister in the blister pack assembly;

FIGS. 38 and 39 depict detail of the hook on the resilient strip;

FIG. 40 is an enlarged view of the blister pack assembly;

FIG. 41 is an enlarged view of an alternative blister pack assembly;

FIG. 42 is a plan view of the blister pack in FIG. 41;

FIGS. 43 and 44 depict a second preferred embodiment of the present invention;

FIG. 45 depicts a perspective view of the third preferred embodiment of the present invention;

FIG. 46 is a partially exploded view of the elements in FIG. 45;

FIG. 47 depicts the inhalation device in FIG. 45 with the outer case closed and the lid partially cut away; and

FIGS. 48<i>a </i>and <b>48</b><i>b </i>depict detail of one of the guide arms of the suction tube in FIG. <b>46</b>.

Reference should now be made to FIGS. 1, <b>2</b> and <b>3</b> which are various perspective views of a first preferred embodiment of the inhalation device <b>1</b> when enclosed in an outer case <b>2</b>. The outer case <b>2</b> is hinged having a typical push-button locking mechanism <b>3</b>. FIG. 4 depicts the inhalation device <b>1</b> when removed from the outer case <b>2</b>. The outer case <b>2</b> is constructed such that the inhalation device <b>1</b> can slide into the base <b>11</b>. The sides of the blister pack assembly <b>5</b> cooperate with the internal surface of the sides of the base <b>11</b> to ensure that the inhalation device <b>1</b> is held securely in the outer case <b>2</b>. In addition, the base <b>11</b> has two latching elements <b>50</b> which cooperate with holes <b>51</b> in the lower tray <b>16</b> (see FIG. 27) which further secure the inhalation device <b>1</b> in the outer case <b>2</b>.

The inhalation device <b>1</b> comprises a suction tube <b>4</b> and a blister pack assembly <b>5</b>. The suction tube <b>4</b> is removably connected to the blister pack assembly <b>5</b> by an elongate resilient strip <b>6</b> which biases the suction tube <b>4</b> away from the blister pack assembly <b>5</b>. The resilient strip <b>6</b> is constructed such that when the outer case <b>2</b> is closed the suction tube <b>4</b> can lie substantially flat against the blister pack assembly <b>5</b>. On opening the outer case <b>2</b>, the resilient strip <b>6</b> will raise the suction tube <b>4</b> such that it can be easily grasped by a user.

The suction tube <b>4</b> is hinged on the blister pack assembly <b>5</b>. The internal surface of the lid <b>9</b> of the outer case <b>2</b> can optionally be provided with arms <b>10</b> which interlock in a snap-action with the proximal end <b>8</b> of the suction tube <b>4</b> when the outer case <b>2</b> is closed. On opening the outer case <b>2</b>, the arms <b>10</b> will cooperate with the resilient strip <b>6</b> to raise the suction tube <b>4</b>. The arms <b>10</b> are constructed to slip over the proximal end <b>8</b> of the suction tube <b>4</b> as the lid <b>9</b> is rotated away from the blister pack assembly <b>5</b> and eventually release the proximal end <b>8</b>, at which point the resilient strip <b>6</b> continues to maintain the suction tube <b>4</b> in the raised position.

In FIG. 3, it is clear how the inhalation device <b>1</b> can slide into the base <b>11</b> of the outer case <b>2</b>. The suction tube <b>4</b> and blister pack assembly <b>5</b> can be removed and replaced when the user has emptied all the blisters <b>13</b> in the blister pack <b>12</b> seen in the exploded view in FIG. <b>5</b>.

The blister pack assembly <b>5</b> comprises a carrier <b>14</b> and the blister pack <b>12</b>. The carrier <b>14</b> has an upper tray <b>15</b> and a lower tray <b>16</b> which interlock and enclose the blister pack <b>12</b>.

In FIG. 6, the elements attached to the upper tray <b>15</b> have been exploded. Suction tube <b>4</b> comprises a body <b>4</b><i>a </i>and an external sleeve <b>4</b><i>b</i>. However, the suction tube <b>4</b> can be moulded as a single part rather than as two separate elements. The body <b>4</b><i>a </i>includes the proximal end <b>8</b> which forms the mouthpiece of the suction tube <b>4</b>. The external sleeve <b>4</b><i>b </i>includes the distal end <b>7</b> and comprises guide arms <b>17</b> which hinge the suction tube <b>4</b> to the upper tray <b>15</b> and facilitate location of the suction tube <b>4</b> in the blister pack assembly <b>5</b>.

FIG. 7 is a plan view of the blister pack <b>12</b>. The blister pack <b>12</b> has a plurality of blisters <b>13</b> arranged in four parallel rows. Each blister <b>13</b> holds a dose of powdered medicament (visible in FIGS. <b>8</b> and <b>10</b>). The blister pack <b>12</b> comprises a lower base <b>18</b> containing a plurality of cavities <b>19</b> and an upper foil layer <b>20</b> which is sealed to the lower base <b>18</b>. There is an optimum minimum sealing distance around a blister <b>13</b> in order to ensure that there will be no or very little ingress of moisture within a cavity <b>19</b> which could contaminate or degrade the powdered medicament. The sealing distance “d” from the edge of a cavity <b>19</b> to the edge of an adjacent cavity <b>19</b> or a cut edge of the blister pack <b>12</b> must typically be at least 2 mm. With this minimum sealing distance in mind, the aim is to reduce the overall size of the blister pack <b>12</b> for a given number of blisters <b>13</b>. However, the blister pack <b>12</b> must also allow penetration of the guide arms <b>17</b> of the suction tube <b>4</b> on each side of a blister <b>13</b> and, therefore, the foil layer <b>20</b> and lower base <b>18</b> must be cut during manufacture of the blister pack <b>12</b>. Although the blister pack <b>12</b> could be cut by removing appropriately shaped slots from the blister pack <b>12</b>, there is the complication of removal of the cut portions of foil and base material. Any cut portions which are not removed could fall into a cavity, sit above a blister or affect the sealing of the foil to the base material. Furthermore, if a slot is cut away from the foil and base material the overall size of the blister pack <b>12</b> would have to increase bearing in mind the minimum sealing distance “d” of 2 mm and any additional width of the slot.

Accordingly, the blister pack <b>12</b> is provided with slits <b>21</b> which are simply formed by scoring both the foil layer <b>20</b> and lower base <b>18</b>. In this way, the minimum sealing distance “d” of 2 mm can be achieved without adding to the overall size of the blister pack <b>12</b>.

Although the guide arms <b>17</b> are constructed such that penetration of the slits <b>21</b> requires little force by the user, insertion can be facilitated by folding the opposed edges of the scored foil and base material downwardly to increase the width of the slit <b>21</b> without affecting the minimum sealing distance “d”. The optional folding of the opposed edges of the slit <b>21</b> can be seen in FIG. <b>10</b> and in FIG. <b>41</b>. Alternatively, the guide arms <b>17</b> can be constructed such that they have a narrower profile than the slit <b>21</b>.

The detailed construction of the suction tube <b>4</b> will now be described with reference to FIGS. 11 to <b>23</b>. In FIG. 11 the body <b>4</b><i>a </i>of the suction tube is depicted. The body <b>4</b><i>a </i>comprises a mouthpiece <b>8</b> which forms the proximal end of the suction tube and a cutting mechanism <b>22</b> at the opposite end. A tapered channel <b>23</b> runs from the mouthpiece <b>8</b> to the cutting mechanism <b>22</b>.

The cutting mechanism <b>22</b> is constructed to penetrate the foil layer <b>20</b> above a cavity <b>19</b> and allow the user to inhale the powdered medicament by breathing in through the mouthpiece <b>8</b>. FIG. 12 is a sectional view in direction X—X in FIG. <b>11</b> and depicts by-pass holes <b>24</b> which will allow an additional air flow to the main air flow from within the cavity <b>19</b>. FIGS. 13 and 14 are additional views of the suction tube body <b>4</b><i>a</i>. The cutting mechanism <b>22</b> includes a cutting blade <b>25</b> and plunger blades <b>26</b> on either side of the cutting blade <b>25</b>. The cutting blade <b>25</b> will actually penetrate the foil layer <b>20</b>, whilst the plunger blades <b>26</b> act to push the cut foil away to create a clear passage for the powdered medicament and ensure that all the powdered medicament can be inhaled from the cavity <b>19</b>.

Details of the external sleeve <b>4</b><i>b </i>of the suction tube <b>4</b> and the resilient strip <b>6</b> can be seen in FIGS. 17 to <b>23</b>.

The body <b>4</b><i>a </i>slots within the external sleeve <b>4</b><i>b </i>forming the suction tube <b>4</b> (see FIGS. <b>5</b> and <b>6</b>). The resilient strip <b>6</b> has a fixed connection <b>27</b> at one end to the distal portion <b>7</b> of the suction tube <b>4</b> and is connectable by a hook <b>28</b> to the upper tray <b>15</b> at the opposite end to the hinging point of the suction tube <b>4</b> on the carrier (see FIGS. <b>3</b> and <b>24</b>). The length of the resilient strip <b>6</b> is such that when the suction tube <b>4</b> sits on the hinge arms <b>29</b> and the hook <b>28</b> is located in the recess <b>30</b> in the upper tray <b>15</b>, the resilient strip <b>6</b> will bend upwardly in an arc. This configuration of the resilient strip <b>6</b> results in the suction tube <b>4</b> being raised on the hinge arms <b>29</b>. However, the resilient strip <b>6</b> is sufficiently flexible to allow the suction tube <b>4</b> to pivot on the hinge into the position where it will lie substantially flat against the upper tray <b>15</b> when the outer case <b>2</b> is closed.

In FIGS. 18 and 19 further details of the guide arms <b>17</b> and resilient strip <b>6</b> are visible. The resilient strip <b>6</b> has a protruding spine <b>31</b> which gives the resilient strip <b>6</b> a shallow “T” shaped cross-section. The protruding spine <b>31</b> is on the underside of the resilient strip <b>6</b> and serves to ensure that the resilient strip <b>6</b> will arc away from the surface of the upper tray <b>15</b>. The arcing of the resilient strip <b>6</b> will result due to shrinkage effects after the moulding of the plastic material from which the strip is made. There is also a thickened portion <b>32</b> adjacent to the fixed connection <b>27</b> which serves to ensure that the resilient strip <b>6</b> does not easily twist or obstruct the slots and holes in the upper tray <b>15</b> during use.

Reference should now be made to FIGS. 20 to <b>23</b> which show details of the guide arms <b>17</b> on the external sleeve <b>4</b><i>b </i>of the suction tube <b>4</b>.

In FIG. 20 the external surface of a guide arm <b>17</b> is depicted. This surface pivots on a hinge arm <b>29</b> on the upper tray <b>15</b>. In this configuration of the inhalation device, the hinge arms <b>29</b> are provided with a stub <b>33</b> and the guide arms <b>17</b> are each provided with a cooperating hole <b>34</b>. In order to facilitate location of the guide arms <b>17</b> on the hinge arms <b>29</b>, each guide arm <b>17</b> has a shallow tapering channel <b>35</b> leading from the outer edge of the guide arm <b>17</b> to the hole <b>34</b>. The channels <b>35</b> help to re-locate the suction tube <b>4</b> on the hinge arms <b>29</b> after each use of the inhalation device. Preferably, the stubs <b>33</b> are a snap-fit in the holes <b>34</b>.

Each guide arm <b>17</b> is also provided with two buttons <b>36</b> which are constructed to be a snap-fit in the slots in the upper tray <b>15</b> and lower tray <b>16</b> (described in detail with reference to FIGS. 31 to <b>37</b>).

FIG. 21 is a sectional view in direction X—X in FIG. 18 of the external sleeve <b>4</b><i>b</i>. In this view, by-pass holes <b>37</b> can be seen which align with the by-pass holes <b>24</b> in the suction tube body <b>4</b><i>a</i>. FIG. 23 is a sectional view in direction X—X in FIG. <b>21</b> and depicts the internal surface of a guide arm <b>17</b>. An enlarged view of the fixed connection <b>27</b> of the resilient strip <b>6</b> to the external sleeve <b>4</b><i>b </i>appears in FIG. <b>22</b>.

FIGS. 24 to <b>26</b> depict the upper tray <b>15</b> of the carrier <b>14</b>. In plan view the rows of holes <b>38</b> and slots <b>39</b> are visible which are configured to align with corresponding blisters <b>13</b> and slits <b>21</b> in the blister pack <b>12</b> (see FIG. <b>7</b>).

The hook <b>28</b> on the resilient strip <b>6</b> is intended to be a push-fit into the recess <b>30</b> when the inhalation device is assembled. The arrow-shape prevents removal of the hook <b>28</b> once pushed into the recess <b>30</b> thereby ensuring that the suction tube <b>4</b> remains connected to the blister pack assembly <b>5</b>. For detail of the hook <b>28</b>, reference should be made to FIGS. 38 and 39 described later. However, the recess <b>30</b> will allow a twisting and sideways movement of the hook <b>28</b> which is necessary to ensure that the suction tube <b>4</b> can penetrate all the blisters <b>13</b> without restriction of movement, in particular, when reaching the blisters which lie at the end of the blister pack <b>12</b> where the hook <b>28</b> is held. The twisting movement of hook <b>28</b> occurs due to the provision of a rib <b>48</b> (see FIGS. 38 and 39) against which the hook <b>28</b> bears, twisting about the point of contact. On each side of the recess <b>30</b> is a locking slot <b>40</b> which cooperates with the push-button locking mechanism <b>3</b> on the outer case <b>2</b>. FIG. 25 is a sectional view in direction X—X in FIG. 24 whereas FIG. 26 is a view in direction A in FIG. <b>24</b>.

The slots <b>39</b> are spaced such that the guide arms <b>17</b> on the suction tube <b>4</b> can penetrate easily. However, the buttons <b>36</b> on the guide arms <b>17</b> are a snap-fit in the slots <b>39</b> to ensure that the suction tube <b>4</b> will remain correctly located once a blister <b>13</b> has been penetrated by the cutting blade <b>25</b> and plunger blades <b>26</b> (see FIGS. 31 to <b>37</b>).

Reference should now be made to FIGS. 27 to <b>30</b> which depict the lower tray <b>16</b>. The lower tray <b>16</b> is constructed such that it can lock into position with the upper tray <b>15</b> when the blister pack <b>12</b> has been inserted. A plurality of guide pins <b>41</b> spaced around the perimeter of the upper tray <b>15</b> are a snap-fit in corresponding sleeves <b>42</b> in the lower tray <b>16</b>.

The lower tray <b>16</b> is provided with slots <b>43</b> which correspond with the slots <b>39</b> in the upper tray <b>15</b> and slits <b>21</b> in the blister pack <b>12</b>. The guide arms <b>17</b> will enter slots <b>43</b> after penetrating the foil layer <b>20</b> and lower base <b>18</b> of the blister pack <b>12</b>. In FIG. 28 it is clear that the slots <b>43</b> have a depth provided by a wall <b>44</b> around the slot extending from the surface <b>45</b> of the lower tray <b>16</b>. The wall <b>44</b> ensures that a guide arm <b>17</b> will enter a slot <b>39</b> in the upper tray <b>15</b> correctly and that the suction tube <b>4</b> remains upright in the carrier <b>14</b> during inhalation of the powdered medicament by the user. By provision of the slots <b>43</b> in the lower tray <b>16</b>, the depth of the lower tray <b>16</b> can be less than if the lower tray was solid, in which case, the depth would have to increase by the thickness of the base material of the lower tray <b>16</b>. Clearly, any constructional feature which reduces the size of the inhalation device or the weight makes the device more advantageous and user-friendly.

In FIG. 29, which is a sectional view in direction Y—Y in FIG. 27, the upright ridges <b>46</b> which help to locate the blister pack <b>12</b> correctly can be seen. However, the ridges <b>46</b> also provide support for the blister pack <b>12</b> when the suction tube <b>4</b> penetrates a blister <b>13</b>. Each blister <b>13</b> will sit between two ridges <b>46</b> thereby ensuring that the blister pack <b>12</b> does not slip within the carrier <b>14</b> during assembly. The connection of the upper tray <b>15</b> to the lower tray <b>16</b> is achieved by the interlocking pins <b>41</b> (visible in FIGS. 24 and 25) and sleeves <b>42</b> (visible in FIG. <b>27</b>). In this respect, reference should be made to the blister pack <b>12</b> in FIG. 5 which is provided with “U” shaped recesses <b>47</b> which sit around the interlocking pins <b>41</b> and sleeves <b>42</b> when the blister pack <b>12</b> is assembled between the upper tray <b>15</b> and lower tray <b>16</b>. The lower tray <b>16</b> is also provided with guide pins <b>49</b> which ensure accurate location of the blister pack <b>12</b> within the lower tray <b>16</b>. During assembly, the blister pack <b>12</b> will typically be placed in the lower tray <b>16</b> first so that it is important to locate the blister pack <b>12</b> correctly thereby making the next step of assembling the upper tray <b>15</b> on the lower tray <b>16</b> relatively trouble-free.

In a preferred embodiment, the guide pins <b>49</b> could have a hooked configuration to hold the blister pack <b>12</b> as well as provide a means for its accurate location.

FIG. 30 is a sectional view in direction Z—Z in FIG. 27, showing details of the slots <b>43</b> and ridges <b>46</b>.

FIGS. 31 to <b>37</b> depict the inhalation device in use when the suction tube <b>4</b> has penetrated a blister <b>13</b>.

FIG. 31 is a perspective view of the inhalation device when the suction tube <b>4</b> has been inserted in the first blister <b>13</b> in the second row from the right of the blister pack <b>12</b>. The resilient strip <b>6</b> now serves the function of ensuring that the suction tube <b>4</b> remains connected to the blister pack assembly <b>5</b>. FIG. 32 is a partial plan view of the upper tray <b>15</b> with the suction tube <b>4</b> inserted in one of the holes <b>38</b> and adjacent slots <b>39</b>. In the enlarged view in FIG. 33, further details are visible of the mouthpiece of the suction tube <b>4</b> and through the suction tube <b>4</b> down to the cutting blade <b>25</b>.

FIGS. 34, <b>35</b> and <b>36</b> are different sectional views in directions A—A, B—B and C—C respectively in FIGS. 32 and 33. The sectional views show clearly how the suction tube <b>4</b> penetrates the upper tray <b>15</b>, the blister pack <b>12</b> and the lower tray <b>16</b>. FIG. 37 depicts the air flow into the inhalation device when a user inhales to empty the contents of the cavity <b>19</b> and corresponds to FIG. <b>36</b>.

In FIGS. 34 and 35, it is clear how the buttons <b>36</b> on the guide arms <b>17</b> snap into the upper tray <b>15</b> and the lower tray <b>16</b> to ensure that the suction tube <b>4</b> remains correctly located during inhalation through the mouthpiece by a user. After inhalation the suction tube <b>4</b> can be removed simply by overcoming the slight resistance of the buttons <b>36</b> when locked in the slots <b>43</b>.

It is also important to note that the suction tube <b>4</b> is constructed such that when a blister <b>13</b> is penetrated, there is an air gap between the suction tube <b>4</b> and the surface of the upper tray <b>15</b> which allows an air flow A (see FIG. <b>37</b>). The distal end <b>7</b> of the suction tube <b>4</b> which comprises the cutting mechanism <b>22</b> is also constructed such that during penetration of a blister <b>13</b>, there will be an air gap between the cutting mechanism <b>22</b> and the perimeter of the hole <b>38</b> in the upper tray <b>15</b>. Furthermore, the blister pack assembly <b>5</b> is constructed such that there is an air gap between the lower surface of the upper tray <b>15</b> and the blister pack <b>12</b> which allows an air flow B (see FIG. <b>37</b>). The air flow A and air flow B into the cavity <b>19</b> facilitate inhalation of the contents by a user.

FIGS. 38 and 39 show enlarged detail of the arrow-shaped hook <b>28</b> on the resilient strip <b>6</b> when located in the blister pack assembly <b>5</b>. FIG. 38 is a sectional view which depicts how the hook <b>28</b> is held in the recess <b>30</b>.

In FIG. 39, which is a view in direction E in FIG. 38, the hook <b>28</b> is seen to be held just below the upper tray <b>15</b>. However, as mentioned earlier the hook <b>28</b> is able to move within the recess <b>30</b> from side to side and twist as the suction tube <b>4</b> moves from blister to blister. The twisting movement is achieved by a rib <b>48</b> against which the hook <b>28</b> bears, rotating about the point of contact.

FIG. 40 is an enlarged sectional view through the blister pack assembly <b>5</b> which shows how the blister pack <b>12</b> sits between the upper tray <b>15</b> and lower tray <b>16</b>. The slit <b>21</b> has been formed by scoring the foil layer <b>20</b> and lower base <b>18</b>.

In FIG. 41, an alternative blister pack <b>12</b> is depicted where the slits <b>21</b> have been folded or pushed downwards making the slit wider without affecting the minimum optimum sealing distance described earlier. With the folded slits <b>21</b>, penetration of the blister pack <b>12</b> by the guide arms <b>17</b> is made easier. FIG. 42 is a perspective view of just the blister pack <b>12</b> in FIG. 41 depicting the folded slits <b>21</b>.

Reference should now be made to FIGS. 43 and 44 which depict the second preferred embodiment of the present invention. In this respect, it should be noted that the blister pack assembly <b>105</b> is substantially different to that in the first preferred embodiment. However, FIGS. 43 and 44 depict an alternative biasing means for raising the suction tube <b>104</b> away from the blister pack assembly <b>105</b> in order that the user can easily grasp the suction tube <b>104</b>. The inhalation device <b>101</b> comprises similar elements to the first preferred embodiment, i.e. an outer case <b>102</b>, an upper tray <b>115</b>, a blister pack <b>112</b> and a lower tray <b>116</b>. It should be noted that the upper tray <b>115</b> is fixed to the outer case <b>102</b> in this embodiment. The lower tray <b>116</b> and blister pack <b>112</b> can slide out of the outer case <b>102</b> when the blister pack <b>112</b> needs replacing. However, the present invention is concerned only with the suction tube raising means which comprises a sprung holding element <b>106</b> pivotable on a hinge <b>129</b> on the blister pack assembly <b>105</b>. The holding element <b>106</b> is biased upwardly by a spring <b>106</b><i>a </i>connected to the pivot point of the holding element <b>106</b> on the lower tray <b>116</b>. FIG. 44 is an exploded view of only the suction tube <b>104</b>, the blister pack <b>112</b>, the lower tray <b>116</b> and the sprung holding element <b>106</b>. The inhalation device <b>101</b> operates in a similar manner to the first preferred embodiment in that as soon as the outer case <b>102</b> is opened the suction tube <b>104</b> will be raised away from the blister pack assembly <b>105</b>. The suction tube <b>104</b> is preferably attached to the holding element <b>106</b> by a flexible cord <b>106</b><i>b</i>. In this way, the user will not be able to lose the suction tube <b>104</b>. The suction tube <b>104</b> has a proximal end <b>108</b> which forms the mouthpiece and a distal end <b>107</b> which carries the cutting elements which penetrate the blisters in the blister pack <b>112</b>.

Reference should now be made to FIGS. 45 to <b>48</b> which depict the third preferred embodiment of the present invention. In this respect, it should be noted that the blister pack assembly <b>205</b> is similar to that in the first preferred embodiment. The main distinction is that the suction tube <b>204</b> is removably hinged on the outer case <b>202</b>.

The inhalation device <b>201</b> comprises similar elements to the first embodiment i.e. an outer case <b>202</b>, a blister pack assembly <b>205</b> (comprising a carrier with a blister pack in the form depicted in FIG. 5) and a suction tube <b>204</b>. Since the main distinction is the hinge mechanism, no specific reference will be made to other features which function in a similar manner to the first embodiment.

Reference to FIGS. 45 and 46 reveals that the guide arms <b>217</b> of the suction tube <b>204</b> are now able to pivot on hinge arms <b>229</b> lying on each side of a moulded recess in the lid <b>209</b> of the outer case <b>202</b>. Each hinge arm <b>229</b> is provided with a stub <b>233</b> which is configured to sit in a hole <b>234</b> on a guide arm <b>217</b> of the suction tube <b>204</b> (see FIGS. 48<i>a </i>and <b>48</b><i>b</i>). In order to facilitate location of the suction tube <b>204</b> on the hinge arms <b>229</b>, each guide arm has a shallow tapering channel <b>235</b> leading to the hole <b>234</b>. The stubs <b>233</b> should be a snap-fit in holes <b>234</b>.

Each guide arm <b>217</b> is also provided with a flexible leg <b>236</b><i>a </i>on which is located a button <b>236</b><i>b</i>. The flexible leg <b>236</b><i>a </i>and button <b>236</b><i>b </i>are an alternative arrangement to the two buttons <b>36</b> in the first embodiment (see FIG. <b>20</b>). It has been found that with certain materials, after repeated insertion and withdrawal of the suction tube <b>4</b> in the blister pack assembly <b>5</b>, the buttons <b>36</b> began to wear which resulted in a reduced snap-fit action and, therefore, less stability when the suction tube <b>4</b> sits in the blister pack assembly <b>5</b>. The flexible leg <b>236</b><i>a </i>in the third embodiment attempts to overcome this potential problem by allowing the resilient force to be adjusted. This increase in flexibility also means that a larger button <b>236</b><i>b </i>can be used which also improves the snap-action when inserting the suction tube <b>204</b> in the blister pack assembly <b>205</b>. It follows that if the material from which the guide arms <b>217</b> are made is the same as the material from which the hinge arms <b>229</b> are made, the stubs <b>233</b> and holes <b>234</b> can also be increased in size to improve the snap-action of the suction tube <b>204</b> in the lid <b>209</b>.

A further difference in the third embodiment can be seen in FIG. <b>47</b>. In this figure, the outer case <b>202</b> is closed and the suction tube <b>204</b> lies adjacent to the blister pack assembly <b>205</b> and lid <b>209</b>. The resilient strip <b>206</b> has several waves <b>200</b> which are preformed when the strip is manufactured. The waves <b>200</b> are constructed such that only when there is a pulling tension on the resilient strip <b>206</b> (see FIG. 45) the waves will unfold completely. The provision of the preformed waves <b>200</b> ensures that when the suction tube <b>204</b> penetrates the blisters in the area close to where the hook <b>228</b> is received in recess <b>230</b> in the blister pack assembly <b>205</b>, there will be a reduced risk of the resilient strip <b>206</b> becoming tangled and interfering with the smooth operation of the inhalation device by the user (comparison should be made with FIG. 31 of the first embodiment where the resilient strip <b>6</b> simply arcs away from the blister pack assembly <b>5</b>).

In use, when the outer case <b>202</b> is opened the resilient strip <b>206</b> is of such a length that when the lid <b>209</b> is fully opened the suction tube <b>204</b> will be pulled away from the lid <b>209</b> in order to facilitate grasping by the user. The user then removes the suction tube <b>204</b> from the hinge arms <b>229</b> and inserts the guide arms <b>217</b> into the blister pack assembly <b>205</b> as shown in FIG. 31, for example.

Although only three preferred embodiments of the present invention have been described in detail, various modifications of the raising means for the suction tube can be envisaged which would also provide the advantages disclosed herein.